This invention relates to halogenated phenyl cyanates. More particularly, it relates to halogenated phenyl cyanates substituted at both ortho positions.
Phenyl cyanate and phenyl cyanate substituted at the para position have been used as reactive additives to modify polymers of polycyanate monomers. Polycyanate monomers are known thermosets that polymerize to form polytriazines. Korshak et al., Polymer Science USSR, A17: No. 1, p. 23-27, 1975, disclose modified physical and mechanical properties of a polytriazine prepared from the dicyanate of bisphenol A and varying amounts of phenyl cyanate. Brand et al., NASA Contractor Report 3185, 1979, disclose reduced water sorption of polytriazines prepared from dicyanates and varying amounts of either 4-nonylphenyl cyanate or 4-phenylphenyl cyanate.
Unfortunately, even though the addition of the phenyl cyanates employed in the art reduces water sorption of the prepared polytriazine, other physical and mechanical properties of the polytriazine are adversely affected. More significantly, Korshak et al., supra, disclose a significant reduction in toughness, as measured by impact strength, relative to a polytriazine prepared without the addition of a phenyl cyanate.
In view of the deficiencies of the prior art, a phenyl cyanate is needed that does not adversely affect physical and mechanical properties of prepared polytriazines. Moreover, a phenyl cyanate is needed that enhances these properties, especially those properties relating to toughness and flame retardance.